Haptics

Comments (0)

Transcript of Haptics

DefinitionHaptic Loop ChallengesFree motion of operator when there is no contactContinuous nature of the physical dynamics and the discrete nature of the computer controlEarly researchLederman and Klatzky, 1987 TextureHardnessTemperatureWeightVolumeShapeMotionFunctionHaptic Interfacegenerate the sense of virtual touch in the form of:force feedback : receptors in the joints like weight, motion tactile feedback : sensors in the skin like temperature, textureIntroductionHAPTICSHaptic Device Design

operator applies the force and constrain the operator`s position to match the appropriate deflection of a simulated object in a virtual world Impedance devicesthe force is applied as a vector to the position of the operator according to computed behavior of the simulated object industrial robots

-Higher order models-Empirical data-Both simultaneously could be usedactuators are controlled to provide appropriate haptic sensations to the human operatorKinematics : Joint angle space is converted to cartesian frame and end effector is haptic interface point(HIP) also called avatar as the virtual representation of haptic interfaceVibration FeedbackRequirements:- low inertia, low friction, low torque ripple & back-drivability - usually open-loop force control (low friction & inertia)Can be used to simulate:-Patterned textures-Roughness etc.

Collision detection : objects are represented by polygons-splines and check if HIP is inside the body, if not then force is zero!Determining surface point : if HIP is in the body, put this on the surfaceForce calculation : due to object geometry or object surface; texture or friction; Basdogan and Srinivasan, 2002:F=kx; x:depth of the penetration k: stiffnesslow k : soft surfacehigh k: undesirable vibrations

Haptic PaddleVibration FeedbackCan also be used for sensory substitution to convey-attention- direction-other information